Six new coordination polymers based on a tritopic pyridyldicarboxylate ligand: structural, magnetic and sorption properties

Using a rigid ligand, pyridine-3,5-bis(phenyl-4-carboxylic) acid (H2L), six new coordination polymers have been synthesized under solvothermal conditions, formulated as [Co(L)(DMF)] (1), [Co(L)(H2O)]·DMF (2), [Co3(L)2(HCOO)2(H2O)2] (3), [Co5(L)4(OH)2(H2O)2]·0.5DMF·H2O (4), [Mn(L)(H2O)]·DMF (5), and [Zn(L)]·DMF (6) (DMF = N,N-dimethylformamide). Complex 1 exhibits a 2D layer structure with a four-connected net. 2 is also a 2D layer net which forms a 2D stacked layers porous framework through hydrogen bonding interactions. In 3, 10-connected clusters [Co3(COO)6] are extended by a L2− linker to construct a 3D (3,10)-connected framework with a (4·6·8)(42·62·810·10) topology net. As for 4, a rare pentanuclear cluster, [Co5(μ3-OH)2(COO)8N4], serves as a 12-connected node to give a 3D (3,12)-connected framework with a larger solvent accessible volume. 5 shows a 2D 44 layer framework by considering Mn(II) as a four-connected node. 6 exhibits a 3D framework based on 1D Zn–(COO)–Zn chains. All complexes have been characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analysis, thermogravimetric analysis and powder X-ray diffraction measurements. The magnetic properties of complexes 1–5 and the photoluminescence properties for 6 have been investigated. H2, N2 and CO2 adsorption measurements were carried out for 4.